Many items used in healthcare settings for patient treatment require storage, treatment and/or preparation at specified temperature or temperature range. For many years, the most common way of taking an item's temperature involved utilization of mercury thermometers. However, such thermometers are susceptible to breaking, releasing substances that often contaminate whatever surfaces they come into contact with. Items, such as those in laboratories, pharmacies, and other areas in a healthcare setting require regular, systematic, and reliable temperature monitoring. These items may include pharmacy refrigerators or freezers containing medications and supplements, blanket warmers, patient and treatment rooms, hot and cold holding units, cryogenic equipment and other items.
Because of the drawbacks of conventional thermometers, electronic thermometers were developed and are now in widespread use. Although electronic thermometers provide relatively more accurate temperature readings than traditional techniques, they nevertheless share many of the same drawbacks. For example, even though electronic thermometers provide faster readings, they must still pass periodic calibration checks before an accurate reading can be taken. Typically, electronic temperature sensors and other thermometers require calibration at the factory during manufacturing in order achieve the quick and accurate temperature reading capability noted above. Unfortunately, known techniques for field calibrating electronic thermometers fail to account for differences (e.g., manufacturing differences, altitude, etc.) in reference temperature sensors and assume that each of the reference temperature sensors responds in the same manner to a given input. Other known techniques may also rely upon the calibration of the primary temperature sensor to provide sufficiently accurate data to extract parameters of the reference temperature sensor.
The proper use and handling of healthcare items requires a constant monitoring of their temperature and/or the temperature of the ambient air in which they are being stored, for example, in medical refrigerators. The collection and maintenance of temperature data is accomplished using various instruments and is generally very labor intensive. For example, it is known to use inspectors who carry portable temperature data collection devices that include a temperature measuring sensor and a data storage device, for example, a digital processor with memory that maintains a digital record of the temperatures measured. The inspectors use the temperature sensor to measure the temperature of the items at different times and at different stages of the handling, preparation and implementation processes. Historical temperature records are kept either manually or are entered into a computer for storage and reporting. Also for example, there are known devices for measuring temperatures and automatically recording those temperatures on a paper chart; however, such devices have relatively limited applications and require additional expenses and maintenance. At a minimum, the temperature data is collected manually and logged on paper temperature sheets attached to each piece of equipment that requires monitoring. But this prevents dynamic analysis of that equipment and again requires labor intensive maintenance.
Recommended temperatures and procedures in healthcare settings and preparation processes are set forth according to State and Federal laws and other regulatory agencies. The calibration procedures are set by the National Institute of Standards and Technology (NIST), which is a federal agency that develops and promotes temperature management standards. Implementation of NIST standards and associated data collection, however, is also very labor intensive and can be prone to errors. Thus, there is a need for a convenient method and system for tracking temperatures of items at different locations and providing a historical temperature record of the item in a healthcare setting and assuring that the temperatures are accurate.
Moreover, conventional methods for calibration of electronic thermometers often utilize temperature-controlled water or other liquid bath to control the temperature of the thermometer, or its components, during calibration. Because know calibration methods require and the temperature instruments to be collected and brought back to the know calibration source it requires extensive labor and time to located, collect, calibrate, log the calibration data, and return the instrument back to its location. This process can take hours if not days or weeks depending on the number of temperature instruments to be calibrated.
One conventional system includes a wireless transmitter that takes temperatures in the healthcare market and must be tested periodically for accuracy. The tests are conducted to a NIST standard by using an oil or liquid bath or hand held fixed value electronic temperature transmitter to provide a single reference or comparable temperature. Some such systems use multiple temperature points to assure accuracy across the temperature range of the sensor, adding an even higher level of complexity. Such calibration systems are very difficult, cumbersome and time consuming to use, especially when a particular healthcare institution has hundreds or more temperature sensors to individually and manually maintain, check, calibrate and re-calibrate.
Accordingly, an improved method for calibrating a reference temperature sensor of a thermometer or temperature sensing instrument in a healthcare or other setting is needed.